PLB vs Satellite Messenger — Which Should You Buy?
PLB vs Satellite Messenger — Which Should You Buy?
Both a PLB and a satellite messenger can summon help in an emergency. They do it in completely different ways and the right choice depends entirely on how you use the water and what you need.
What a PLB Does
A Personal Locator Beacon transmits a distress signal on 406MHz via the international Cospas-Sarsat satellite network when activated. The signal goes directly to a rescue coordination centre. No subscription. No monthly fee. Just a single, unambiguous distress signal that tells the coastguard or appropriate authority exactly where you are and that you need help.
A PLB does one thing: call for emergency help. It cannot send a message. It cannot receive anything. It cannot tell someone you are fine. Press the button and rescue services respond.
What a Satellite Messenger Does
A satellite messenger — devices like Garmin inReach, SPOT, or Zoleo — operates via a commercial satellite network such as Iridium. It allows two-way text messaging, position tracking, and an SOS function. You can send a message saying where you are and what is happening. You can receive a reply. You can check in so people ashore know you are safe without triggering a full emergency response.
The SOS function on a satellite messenger sends an alert to a private rescue coordination centre operated by the device manufacturer, which then coordinates with the appropriate coastguard or emergency service.
Satellite messengers require a subscription — typically £15 to £50 per month or an annual fee.
The Key Differences
| Option | PLB | Satellite Messenger |
|---|---|---|
| Subscription | None | Required |
| Two-way comms | No | Yes |
| Emergency network | Cospas-Sarsat (government) | Commercial (Iridium/Globalstar) |
| Tracking | No | Yes |
| Cost | £200-£400 once | £200-£500 plus subscription |
| Emergency use | Yes | Yes |
| Non-emergency use | No | Yes |
Which Should You Choose?
For offshore sailors and maritime workers who want the most reliable, no-subscription emergency distress system — PLB.
For long-distance cruisers, solo sailors, or anyone who wants two-way communication and position tracking as well as emergency capability — a satellite messenger combined with a PLB gives the best of both worlds.
For someone who needs only occasional emergency backup for recreational sailing — PLB is the simpler and lower-cost choice.
Can I Have Both?
Yes — and for serious offshore use, having both is not unreasonable. The PLB is your primary emergency device using the government-funded Cospas-Sarsat network. The satellite messenger is your daily communication and tracking tool. They serve different purposes.
FAQs
Is a PLB or satellite messenger better for solo sailing?
Both have their place. A PLB is the non-negotiable safety baseline — it works anywhere with no subscription and uses the most widely recognised distress network. A satellite messenger adds check-in capability and two-way communication. For solo offshore sailing, both is the honest recommendation.
Does a satellite messenger replace a PLB?
Not fully. The Cospas-Sarsat system that PLBs use is internationally mandated and coastguards worldwide are set up to respond to 406MHz alerts. Commercial satellite networks vary in how well they integrate with local coastguard systems. For maritime use specifically, a PLB using the GMDSS framework is the more universally reliable distress option.
Always carry appropriate emergency signalling equipment for your specific activity and operating area. marinesafetyguide.com participates in affiliate programmes including Amazon Associates and may earn a small commission on purchases made through links on this site.
